CATALYTIC ACTIVITY OF IRON-ALUMINUM OXIDES IN THE LIQUID-PHASE OXIDATION OF HEXADECANE AND CUMENE

A study has been made of the catalytic activity of iron-aluminium oxid es FexAl2-xO3 obtained by alkoxosynthesis in the liquid-phase oxidatio n of hexadecane and cumene (343-433 K). The interrelation between the structure of iron-aluminium oxides, studied by means of Mossbauer spec troscopy, static magnetic susceptibility and EXAFS, and their catalyti c activity has been established. The role of electron-excited terminal oxygen in surface superparamagnetic clusters of gamma-Fe2O3 as an act ive oxidation initiation centre is discussed. By the kinetic method of combined initiation it has been shown that iron-aluminium oxides take part only in the stage of initiation of oxidation with subsequent dev elopment of the reaction within the liquid phase by a homogeneous mech anism. The kinetic parameters of low-temperature oxidation of cumene i n the presence of the systems synthesized have been determined. It has been established that the rate of heterogeneous initiation of the rea ction in their presence amounts to (5-7) x 10(-7) mole/l-sec (343 K), which is three orders of magnitude higher than the corresponding value s for a number of simple oxides.